CONCORD, CALIFORNIA – The Contra Costa Mosquito and Vector Control District (District) reports two more groups of trapped mosquitoes and one dead bird have tested positive for West Nile virus (WNV), while three sentinel chickens have tested positive for antibodies in Contra Costa County.
The mosquitoes were collected in traps in the City of Martinez and Bethel Island this week. The dead bird is an American crow from San Ramon and the chickens are from Holland Tract.
In addition to these mosquitoes, chickens, and dead bird, there have already been two groups of mosquitoes and four dead birds that have tested positive for WNV, and five sentinel chickens have tested positive for antibodies in 2024. In response to the newest WNV activity, the District is increasing surveillance and mosquito control efforts.
“Mosquitoes known to transmit West Nile virus sometimes lay eggs in backyard water sources, and the adults that emerge from those sources can affect an area of up to 15 miles, so, it is very important for Contra Costa County residents to dump out any containers holding standing water on their property, use an insect repellent if they are outdoors in the evening or early morning, and report mosquito issues to the District, because it only takes one bite from an infected mosquito to transmit West Nile virus to a person,” said Steve Schutz, Ph.D., Scientific Program Director.
To reduce the risk of mosquito bites, the District recommends residents use an EPA-registered insect repellent with one of the following active ingredients:
- DEET
- Picaridin
- The repellent version of Oil of Lemon Eucalyptus
- IR3535
Always follow the instructions on the label when using insect repellent.
To reduce the risk of mosquitoes on residential properties, the District recommends Contra Costa County residents look around their front and backyards at least once a week and dump out any amount of standing water. Also, check window screens to make sure they fit properly without any gaps or rips in the screen.
Contra Costa County residents can report dead birds by phone at (877) WNV-BIRD (968-2473) or online. County residents can also request mosquito service for residential property by calling (925) 685-9301 or online. Signing up for District notifications allows Contra Costa County residents to receive information on West Nile virus activity and Adult Mosquito Control operations in real-time. Subscribe to District publications here.
Recent
- Aug 12 – Again… Adult Mosquito Control to Occur Monday in Oakley
- Aug 9 – West Nile Virus-Infected Mosquitoes Confirmed in Oakley
- Aug 9 – Tonight: Adult Mosquito Control to Take Place in Oakley
- July 26 – First West Nile Death Since 2006 Reported in Contra Costa County
- June 21 – West Nile Virus-Infected Birds Confirmed in Concord
- April 27 – First West Nile Virus Positive Dead Bird of 2024 Found in Contra Costa County
